1. Field of The Invention
The invention relates to an articulator having two mountings mounted on its arms and adjustable and fixable in relation to one another, the said mountings having holders or supports, one for the mandibular model and the other for the maxillary model, and being disposed on adjustable, spherical axial bearings.
Such an articulator, which, among other things, reproduces the movement of the mandibular articulation, makes it possible to fix the two corresponding plaster casts of the patient's jaws in the attitude in which they would meet in their natural position in the patient's mouth. The correctly positioned transfer is accomplished by known means, such as face bows, a wax index, horizontal guides etc. With the fastening of the plaster model, which can be accomplished in a single procedure for both casts, or separately for the maxilla and mandible, the mechanically set simulation of the natural jaw movement is possible, which is essential to the further operations.
2. Discussion of The Prior Art
The fastening of the plaster jaw models in the articulator is accomplished by the use of plaster, whereby the plaster cast is joined to its mechanical holder as used in the apparatus. The mechanical holders or supports can consist, for example, of a holding yoke, which is molded into the model. These model holding yokes can also be attached to the articulator by a stud connector. It is furthermore known (U.S. Pat. No. 2,621,407) to fasten the model to the arms of the articulator by means of ball joints, the ball joint for the maxillary model being locked in relation to the articulation of the articulator, thereby simultaneously preventing any change in the level of the plane of occlusion with respect to the articulation. The cross table movements to the performed in the horizontal plane can be achieved only with the mandibular model or model holder, two sliding members being provided which are adjustable at right angles and disposed one above the other, and which are fixable by means of screws in each case.
Merely to coordinate the mandibular model with the maxillary model, numerous screws must therefore be adjusted or set independently of one another, which renders continuous shifting of the mandibular model unfeasible, the danger additionally existing that previously set adjustments might be altered.
Other known articulators have claws for gripping the plaster model. These models can easily be removed, but they cannot be installed with reference to coordinates, and they do not permit arbitrary alignment or three-dimensional adjustment of the two models to one another. Furthermore, it is not possible to perform corrections of the positions of the plaster casts as might appear necessary or desirable, by means of the holding device.
It is therefore the object of the present invention to expand the usefulness of such an articulator and to achieve a coordinate-referenced alignment of the two jaw models with one another and with the mandibular articulation and articulator articulation without having to alter the fastening of the model to its mounting for this purpose.